Personally I think you are better writing your own bass lines using a DAW. Bass is such an important part of the song and the bass line should be logical and rhythmic. The bass RealTracks will often jump about in an unmusical fashion which is a shame. As a result I normally play my parts in using a midi keyboard and a vst like Trilian. After that I edit the timing so it sits well with the drums. I actually enjoy producing the bass line and think it is essential to the success of a track.